Field of the Disclosure
The present disclosure is directed to a passive blow back prevention device for preventing reverse rotation of a torque-transmitting rotatable shaft such as that implemented to deploy and retract an aircraft flap.
Description of Related Art
An aircraft may include one or more flaps 2 in a trailing edge flap system 1 (see, e.g., FIG. 1A). Generally, each such flap 2 may include multiple geared rotary actuators (GRAs) and, in such instances, the outboard GRA 3 support load may be significantly higher than the inboard GRA 4 support load.
As such, the main blow back prevention device 5 (“main no-back”) for the inboard GRA 4 may be designed with a relatively high gain to prevent blow back of the trailing edge of the flap 2 in the event of an operational issue with the main no-back 6 of the outboard GRA 3, combined with a disconnect of a torque tube 7 disposed inboard of the inboard GRA 4 (see, e.g., FIG. 1B).
However, a high gain no-back device may cause system chatter and/or a lock-up of the flap drive system. A lower gain no-back device may reduce or eliminate system chatter, but may not provide adequate blow back prevention in instances of the operational condition previously described.
As such, in some instances, a supplemental blow back prevention device 10 (“half-system no-back”) may be provided. Generally, a conventional half system no-back 10 may include a ratchet and multiple skewed roller friction plate constant drag device.
In light of the state of the art, there exists a need for a supplemental blow back prevention device, for example, for a trailing edge flap system, that addresses issues such as size/compactness, weight, complexity and number of components, cost active versus passive operation, and capability of providing an indicium of issues with the trailing edge flap system without requiring a complex inspection procedure, any or all of which may be lacking in conventional arrangements using conventional blow back prevention devices.